1. Field of the Invention
The present invention relates to semiconductor devices, and more particularly, to a semiconductor buffer memory having a cube shape that minimizes the memory size needed for image rotation and to allow addressing to be performed with a simple logic, and an image capture device and display device including the same.
2. Description of the Related Art
When an image capture device (e.g., a digital camera) rotates a captured image to store it in a main memory or rotates an image stored in the main memory to display it, conventionally a two-line memory buffer may be used. For instance, to rotate a 1024×768 image by 90 degrees with a 32-bit bus and 4-burst transaction, a 2×16×768 byte (about 24 Kbyte)-line buffer memory is needed. When the burst size of access transaction of the buffer memory increases, the performance of image rotation also increases. However, to increase the burst size, the size of the buffer memory needs to be increased, which is not desirable for the compactness of the image capture device. Moreover, conventionally, the size of the buffer memory cannot be decreased and, since a read or write address is not fixed, it is difficult to design the buffer memory in hardware.
FIG. 1A is a schematic diagram of a conventional buffer memory for explaining the write/read operation of a conventional buffer memory for rotating an image. Referring to FIG. 1A, a display device needs to continuously output an image using raster scanning and to read the image in a rotated state, and therefore, the image cannot be read until the image is entirely written to a line buffer memory.
As illustrated in greater detail in FIG. 1B, an image needs to be continuously output to a display unit 13 in raster scan order, and for this operation the image has already been written to a buffer memory 12 to be read in a rotated state. In addition, to accomplish real-time display, while the display unit 13 is reading first data of a certain size from one line of buffer memory (e.g., a second line buffer 12-2) included in the buffer memory 12, a second data of the certain size is read from the main memory 11 and written to another line buffer memory (e.g., a first line buffer 12-1) included in the buffer memory 12.
Accordingly, the conventional buffer memory 12 includes the two line buffer memories 12-1 and 12-2 and uses a method of writing an image, which will be read in a rotated state, to one of the two line buffer memories 12-1 and 12-2 while another image is being read in a rotated state from the other of the two line buffer memories 12-1 and 12-2. This conventional buffering method for image rotation requires a large memory size, and therefore, it does not facilitate the miniaturization of image capture devices or display devices.